There is an acute need for new insecticides and acaricides. Insects and mites are developing resistance to the insecticides and acaricides in current use. At least 400 species of arthropods are resistant to one or more insecticides. The development of resistance to some of the older insecticides, such as DDT, the carbamates, and the organophosphates, is well known. But resistance has even developed to some of the newer pyrethroid insecticides and acaricides. Therefore a need exists for new insecticides and acaricides, and particularly for compounds that have new or atypical modes of action.
US patent application Ser. No. 09/048,601, filed Mar. 26, 1998, dicloses a genus of insecticidal 3-(substituted phenyl)-5-thienyl-1,2,4-triazoles. The disclosed compounds are primarily active against mites and aphids. It has now been discovered that a particular subclass of the genus disclosed in the '601 application have greatly improved activity against other insects, such as whitefly.